Hoisting device



Dec. 15, 1959 c. H. ARNOLD HOISTING DEVICE 2 Sheets-Sheet 1 OriginalFiled June 9, 1955 INVENTOR. CARTER H. ARNOLD BY a WW A 7' TORNE VS Dec.15, 1959 c. H. ARNOLD 2,917,278

HOISTING DEVICE Original Filed June 9, 1955 2 Sheets-Sheet 2 INVENTOR.CARTER h. ARNOLD A T TORNE VS United States Patent M HOISTING DEVICE hCarter H. Arnold, Redwood City, Calif.

Original application June 9, 1955, Serial No. 514,305,

now Patent No. 2,756,947, dated July 31, 1956. Divided and thisapplication May 28, 1956, Serial No. 587,875

3 Claims. (Cl. 25'4150) This invention relates to hoisting devices ofthe type generally employed to support. scaffolds and is similar2,917,278 Patented Dec. 15, 1959 ice Fig. 6 is an enlarged sectionalview of the drive mechanism of the device of this invention; and,

Fig. 7 is a sectional view of one form of drum of the device of thisinvention showing representative dimensions thereof.

In detail, this invention comprises a housing which includes a pair ofsimilar, spaced, opposed, parallel side plates 1, 2 which are securedtogether adjacent their upper edges by means of studs 3, 4 and adjacenttheir lower in general operation to that shown in my United States aPatent No. 2,742,261, issued April 17, 1956. This application is adivision of application Serial No. 514,305, filed June 9, 1955 nowPatent No. 2,756,947.

Heretofore, various hoisting devices have been proposed to avoid thepiling up of rope on the drum carried bythe scaffold which is to beraised or lowered. Such devices include one or more drums around whichthe rope is reeved in such a way that the friction between the rope andthe drum is intended to be sufficient to prevent slippage. In thismanner, the hoisting device and its associated load in effect travelalong the length of rope and no piling up of the latter results at anypoint.

. Although such prior art devices are theoretically correct, none hasbeen adopted in practice because of various disadvantages such asunnecessary weight, lack of inherent safety in operation,impracticability in'operation, complexity, and costliness. Y

On the other hand, this invention contemplates a hoisting device havingmany refinements over the prior art devices resulting in a compact,efficient, and inherently safe hoist. r J f It is therefore a mainobject of the present invention to .provide a hoisting device forscaffolds and the lik e which overcomes the disadvantages of prior artmechanisms of like nature. I I

Another object of this invention is the provision of a hoisting deviceincorporating novel safety features which render the same'foolproof inoperation. I 1

Still another object of this invention is the provision of a hoistingdevice for scaffolds .which' includes m'eans for preventing theformationrof slack in the'gsuspending I rope at any point along thelength of the latter so that the said rope is under control at alltimes.

Yet another object of this invention is the provision of a hoistingdevice adapted to be run along the length of a rope and WhlCh'lS morecompact than those heretofore available. I

. It is a further object of this invention to provide a hoisting'deviceincluding means for automaticallyftightem ing successive ropewindings ona drum to insure adequate frictional engagement therebetween.

; Otherobjects and advantages will becomeiapparent.

from the following description taken in co ection with the accompanyingdrawings,1in which:

Fig; 1 is a top plan view of the hoistingdevice-of this invention,partly broken away on the drum thereof; 1 1 q Fig. 2 is an elevationalview of one side ofthe device of Fig; 1, partly broken away toshowinternal structure; ,Fig. 3 is a sectional view taken generallyalong lines 3 -3-of Fig. 2; l 3 i Fig. 4 is an elevational view oftheother side of the device of Fig. 1;

Fig. Sis a sectionalview taken to show the rope windings generally alonglines -.F s. i

edges by studs 5, 6; Said stubs may be reduced in the diameter at theirthreadedends or provided with tubular spacers 7 (Figs. 1, 3) so thatside plates 1,2 may be positively spaced apart a predetermined distance.Although this invention will be described assuming that side plates 1, 2are disposed vertically, it will be understood that the inventioncontemplates various different applications and in many instances thehoist may be used so as to dispose the side plates other thanvertically.

Extending between side plates 1, 2, substantially centrally of thelatter, is a shaft 8 to which is fixedly secured a drum, generallydesignated 9. Shaft 8 is rotatably mounted in bearings 10 (Fig. 3) whichare preferably press fitted in side plates 1, 2. Said shaft may be heldfrom axial movement by snap rings 11 and prevented from rotating withrespect to drum 9 by a key 12,

Drum 9 is preferably provided with four peripherally extending, axiallyspaced grooves, although a greater or lesser number may be employed. Asbest seen in Fig. 7 said grooves are numbered 13, 14, 15, 16,respectively, and are preferably U-shaped or semicircular in cross section. Thebottom of said grooves are undercut or recessed at 17 for thepurpose of maintaining said grooves in the same shape by promoting evenwear.

Grooves 13-16 areadapted to receive therein the windings o'r turns'of arope, preferablywire rope, with the opposite ends of said rope extendingaway from the drum in opposite directions. Thus, referring to Fig. 2,run 18 of the rope extends upwardly from drum 9 and run 19 extendsdownwardly therefrom. Hereinafter, run 18,will becalled the loaded runand run 19, the unloaded run. Between said runs the rope is formed withthree turns, that is, one less than the number of grooves, anddesig-Hated-.23, 24, 25, respectively, in the drawings. Spaced upwardly fromdrum '9, but relatively closely adjacent the periphery thereof are threerollers 26, 27, 28 which extend between side plates 1, 2 and arerotatably mounted at their ends therein by pressed bearings 29 (Figs. 2,3). The peripheries or rope-engaging surfaces ings is preferably the arc32 of a circle about center 30.

The effect of' the. above described structure is' that the rope is neversubjected to a sharp change in direction and at the same time anextremely compact means is provided" for guiding a portion of thewindings in a path spaced from the periphery of drum 9 and for leadingthe rope from one groove to the adjacent groove.

As best seen in Figs. 1, 3, 5, turn 23 of the rope engages more than 180degrees of groove 13, then joins with turn 24- in groove 14 and thenturn 25 in groove 15.

From groove 15 the rope runs over rollers 26, 27, 28

and enters groove 16 of drum 9-from which said rope extends diagonallyover bolt 6 of the housing and down wardly into unloaded run 19. The areof contact between the rope and drum 9 is about 240 degrees in the caseof each winding; and, as is apparent, the efliciency of the. device isdirectly proportional to this are of contact, which in the present. caseis much greater than the usual 180 degrees. 7

- Fig. Lshows the rope turns as they appear when drum 9 is being rotated(in a manner to be described) so'that loaded run 18' is. being wound onthe drum. In such a case theportions of turns 23, 24', 25 that are ontherside of the drums opposite run 13 extend in the plane of the groovesfrom the. periphery of drum 9 to roller 28. The turns then becomeslantingly disposed .to enter the adjacent grooves on the other side or"said d'mrn, When the drum: is being turned so as to wind unloaded run.19

upon. the drum, the slanting portions become planar a pair of spacedradial flanges 31(Figs. '1, 3, 5) at points adjacent the outermostgrooves 13, 16. on drum 9,

' Flanges 31, assist in guiding the rope turns from grooves 011 oneside-to adjacent grooves on the other side of said drum and to helpprevent. fouling of the rope turns. The; natural shifting of the ropeturns, as above described, caused. by changes in the tension of therope, is not impeded in. any way by rollers 26, 27, 28. However,itshould be noted that the use of a grooved drurn' instead of therollers shown, as has been. attempted in the past, would. result in thewearing and chafing of the rope which is not present in the instantdevice.

The provision of rollers 26, 27, 28 and their positioning-as, abovedescribed is an'extremely important feature of the invention as saidrollers provide a compact means for switching the turnsof the rope. Thepresent invention also. contemplates, other means for performing the ifunctions of. the rollers 26,28. In any case, it is important that thecentral of the. locus of all'points ofengagement of the rope: should bewithin. theperiphery of I drum Since; vention; is dependent uponfriction between the rope and the grooves in drum 9, it has been foundthat increa ing the'radiusfrom the drum center of at least one groovethe operatiotr of: the hoisting device of this inon the sideadjacent theunloaded run 1? causes auto- 7 matic tightening of the'turns 23, 2d, 25on said drurn.

For instance, ifthe diameter of the drum at groove 13 is. 6 and the,diameter at: groove. 14. or 15 is' incfreaicd to 6.010", winding 2,4 or25 .is forced to 'assumesuch larger diameter and thereby increaseftheoverallitension inthewindings- Too great a diflerencein groovediaineters may cause, too muchtension to beapplied to the windings. H lIt, has been; found that, inva hoist for use'with aY d ameterrope, adrum of 6"nominal diameter is adeguate. This nominal; dimension isinoted by the letter'A in F g. 7. I Within manufacturing:tolerances it ispreferableto' progressively increase the drum diameter by an increment,X, of 0:910". Hence, the diameter at groove 14 1 s shown as A-FX, atgroove 15 as A+2X, and at groove 16 as A+3X. Since each groove is ofa'semirope asfwould cause the formation of-slack;

rollers .which. simultaneously engage all'of the turns. on

in. Fig. 2. Plates 34 are generally curved with the rollers 36, 37'mounted adjacent the ends thereof and with the center swingablysupported by means of a pin'38 to one end of an arm 39 which,.in turn,is swingably, mounted intermediate its ends on stud 5. The end of arm 39opposite pin 38 is connected to toggle means, generally designatedAO,forurging said arm in a direction to' force rollers; 36, 37 intoengagement .with the rope in groove 16 (clockwise in-Eig..2)'. 7 V

Toggle means .40 comprises a. lever 41'. pivoted as by pin 42. to saidopposite end' of arrn39; At a point'spaced' from pin 42 a pin43.pivotally connects lever 41 013. red 44 which; is slidably mounted inan anchor pin 45,

which, in turn, is. rotatably mounted on side plate 2. of

the housing. A compression spring 46, surroundingrod -44, isinterposedbetween anchor pin 45 and a shoulder that the. axis of pin 43is placed slightly'inwardly" from a line between the axis'of pins 42 and45 so thatspring 46 also retains lever 41 in the locked position withinthe housing. I. t 1 V "'Tensioning device 35 exerts a radially inwardly.directed pressure along a substantial length of the rope be cause of,thepresence of the two rollers 36, 37 In addition, because both rollersare: pivoted as a unit about the pin 38, each roller exerts. the sameamount of force and there. are noforces exerted along the length of Thefact that rollers 36,. 37' engage only thelastturn of the rope adjacentthe-unloaded run is extremely'irnportant: in preventing the :formationvof. slack and results in'the; rope. being under some tension atallpoints'along the turns,that engage. the grooves. 13 -16. When thehoist is employed tosupport a scaffold from.

. 1 a vertically extending rope fixed at its upper end to the top; of abiulding, loaded. run 18. supports the load and circular crosssection,'. as., previously explained, of substantially the same diameteras the rope,; this increment PPr m t v /30ef the'diameter'ofthe groovecross .sectione C I I It will be noted that thediiferencesiofthe'grooves from 1 the axisof drurn 9-may be varied' indifferentmanners. To; achieve the results of tightening the.windings,-=-it is necessary only that one of the grooves on the'side ofthe. loadedrun 18 be. ata lesser-distance from the axis of drum 9 thanone of the: grooves on the sideof theun loadedfrun 19..

. To. provide an; additional restraint for the rope turn and. to keepthem at all times in engagement with the drurnwgrooves, it is preferableto provide a tensioning" device generallyzdesignated, 35 (Fig 2) forpreventing slack", in-the rope turns. Heretofore analogous devices whichhave been employed but have" generally comprised length of run unloadedrun 19 supports only its own weight. It-will beapparent, therefore, thatthe tension in the ropewill 7 decrease from .run 18 through turn s 23,24, 25'and will 'be relatively small at'v the point engaged bytensioning device, 35. The. latter should, of course,- be on the sideofthe'drurnopposite that from which run 18' extends. It is due to thefact: that the tension on the ropeis slight adjacent run. 19' that thetensioning device must exert a radiallyfinwardly' directed: forcewithout drag asabove described. The lower run 19; of course, resistsonly its own weight an'd'such weight contributes: to the tightness ofthe ro'pe t'urns on the drum. 7 However, even when the 19 is only a fewinches, there is no chance plate 2 of thehousing.v Gear 50 is in meshwith a pinion 51 mounte'don a shaft 52. which is rot'atably supported ain pressed bearing 53 in side plates 1, 2. p

As seen .in' Fig. 3'; pinion 51 is mounted outboard on shaft 52 on thesame side of the housing as gear 510. On

the

the other-end of said shaft, adjacent side plate 1, shaft 52 a frictiondisc 58, and a pressure nut 59. Friction disc,

56, 58 and ratchet wheel 57 are rotatable on shaft 52. The outer end ofsaid shaft is provided with threads 60 for threadedly receivinginternally threaded pressure nut 59. It will be seen that rotatingnut 59with respect to shaft 52 in one direction causes said nut to jamfriction disc, 58, ratchet wheel 57 and friction disc 56 togetheragainst each other and friction plate 54.

Pressurenut 59 may be providedwith an elongated handle 61 for handoperation of the'hoist or may be gear connected to a motor or the likein the event power operation of the 'hoist is desirable. Rotation of nut59 in an opposite direction, to cause said nut to back off from sideplate 1, allows friction plates 56, 58, ratchet wheel 57 and frictiondisc 54 to separate and become freely rotat-- able. one with respect tothe other. A lug 62 is provided protruding axially from nut 59 into thepath of a pin 63 projecting radially from shaft 52 (Fig. 1) forpreventing travel of'nut 59 off the end of shaft 2.

In Figs. 1, 2, it will be noted that a ratchet dog 64, rotatably mountedon a shaft 65 extending from the housing, extends into engagement withthe teeth in ratchet wheel 57. Dog 64 is yieldably urged into suchengaging position by a torsion spring 66 for preventing rotation of saidratchet wheel in the direction indicated by arrow 67 in Fig. 2. Thedirection of arrow 67 is that taken by shaft 52 upon rotation of drum 9to unwind loaded run 18 therefrom or in moving the hoist down the rope.

Threads 60 are formed such that, when handle 61 is moved in a clockwisedirection in Fig. 2 to wind loaded run 18 onto drum 9, nut 59 travelsinwardly to press friction plates 56, 58, ratchet wheel 57 and frictionplate 54 into a single revolvable unit. Hence, the rotation of handle 61will be transmitted to drum 9 through friction plate 54, shaft 52,pinion 51, and spur gear 50. Ratchet wheel 57 will move in a directionopposite arrow 67 merely resting against or clicking by dog 64.

Once the load of the hoist and attached scaffold is placed on run 18,and the clockwise movement of handle 61 is ceased, drum 9 and thereforeshaft 52 will be urged in a reverse direction by the tension in run 18.Handle 61 will rest-in a vertical position because of its own weight.This reverse movement of shaft 52 also jams pressure nut 59 into mutualfrictional engagement with friction discs 56, 58,"ratchet 57 andfriction plate 54. Since ratchet wheel 57 is prevented from moving inthis reverse direction;(arrow 6 7) by dog 64, the hoist cannot fall.

Move me nt of-handle 61 in a counter clockwise direction, however,decreases the frictional pressure between the friction discs, theratchet wheel and friction plate 54 to an extent sufficient to allowshaft 52 to slip with respect to said ratchet wheel. This slippage ofshaft 52 is at all times controlled by the movement of pressure nut 59by handle 61, and therefore the downward movement of the hoist on therope is adjusted as desired by the operator. If, at any time, counterclockwise movement of handle61 is stopped, shaft 52 immediately catchesup thereby jamming friction disc 56 between friction plate.

54 and ratchet wheel 57 to prevent further downward movement of thehoist.

It is obvious that other means could be used to urge nut 59 and theassociated parts of the clutch 55 into mutual frictional engagement sucha face cam secured on shaft 52 and engageable with a mating cam on nut59. The clutch device shown in Fig. 6, however, has been founded to bemore practical.

Rigidly mounted on stud 3 adjacent side plate 2 is a grooved guide orfairlead 69 (Figs. 1, 2, 4) having its grooved edge in line with loadedrun 18 extending from drum 9. In effect, groove 70 completestheprojected half. circle of groove 13 on said drum. Fairlead 69 thereforeacts to guide run 18 into groove 13.

As a valuable safety feature the present invention includes an elongatedclamping arm generally designated 71 (Figs. 1, 2, 4), which cooperateswith guide 69 in a manner now to be described. Arm 71 may be formed froma heavy plate and is swingably supported intermediate its ends on a stud72 extending between and secured to side plates 1, 2. Arm 71 is coplanarwith fairlead 69 and is formed with an arcuate, grooved end 73 toreceive the side of loaded run 18 that is opposite the side engaged byfairlead 69. i

End 73 of arm 71 is formed to the arc of a circle having a centeropposite stud 72 from end 73 so that clockwise swinging of arm 71 (Fig.2) urges the grooved end 73 to clamping relation with fairlead 69 so asto clamp the rope run 18 therebetween(Figs. l, 4). The end 74' of arm 71that is opposite the clamping end is relatively long and of sufiicientmass to urge the arm into clamping engagement of upper run 18 of therope at all times due to gravity.

rotate drum 9.clockwise (Fig. 2) the housing will tend to movedownwardly relative to run 18 and securely clamp the rope againstfairlead 69, thereby positively preventing such downward movement.However, if it is assumed that drum 9 is positively rotated so as towind the run 18 therein, the housing moves up relative to stationary run18 and swings arm 70 counterclockwise away from clamping position (Fig.2). It will be understood that arm 71 is always in engagement with run18 but has no effect thereon except when the housing tends to fallrelative thereto. When it is desired to move the housing downwardrelative to run 18, it is merely necessary for the operator to lift theend 74 of arm 71 outof clamping engagement with run 13. This may befacilitated by running the device upwardly slightly. 9

With respect to Fig. 2, it is obvious that a spring may be employed tourge arm.71 in a clockwise direction into clamping engagement withloaded rope run 18. The arm illustrated has sufiicient unbalanced weightin the portion 74 to effect a proper automatic working of the safetydevice when used with a vertically extending rope. However, additionalyieldable urging on the arm may be desirable in many instances,especially when the device is employed with a rope inclined to thevertical or the horizontal. As previously mentioned, the novelcombination of clamping arm 71 and fairlead 69 also functions to guiderun 18 into the groove 13 on drum 9 at all times, and there is no chanceof the rope separating from fairlead .69.

merely necessary to prevent the accidental rotation of drum 9, if anadditional safety device is desired. To this end a pawl 75 (Fig. 4) maybe swingably mounted on the end of shaft 65 opposite dog 64 and outboardof side plate 2 (Fig. 5). Said pawl is unbalanced so as to be urged intoengagement with the teeth of gear 50 (Fig. 4) by gravity. It is obviousthat a spring could be used to yieldably urge pawl 75 into engagementwith gear 5'!) if required. Pawl 75 is shaped so as to preventcounterclockwise rotation of gear 50 (Fig. 4) which is equivalent todownward movement of the housing with respect to the rope.

In order that pawl 75 will be disengaged from gear 50 only uponunclamping of the brake arm 71, pawl 75 is provided with a pin 76eccentric with respect to shaft 65 and extending axially thereof throughan open ing 77 in side plate 2 into the path of end 73 of clamping arm71. Hence, upon rotation of arm 71 in a clockwise. direction (Fig. 4) tounclamp run 18 of the rope, end 73 strikes pin 76- to rotate pawl 75.outot engagement with gear 50; This allows downward movement ofithehoist with trespect to run 18 ofthe' rope in themanner'previo'uslydescribed. f V p 7 Although the present invention hasmany applications;

its greatest use, lies in supporting scaffold or the like from a pair ofstirrups or hangers 78' (Fig; 4') at op posite ends thereof, in whichcase a hoisting device is" employed with each such stirrup.,Ordinaril'y, such stir-' rups are formed from steel rod or strap andare provided with an eye portion 79 from which the scaiiold issuspended. In such a case side plates 1, 2 are preferably. provided withan offset portion so that stud 5 is in vertical alignment with loadedrun 18i of. the rope. I

v In order'to position the eye portion 79 in vertical alignment with therun 18, the former may be directly carried by stud 51in Fig; 4. Apositioning collar on" stud '5 may serveto 1101a the vertical alignmentbetween run 18 and the eye 79 of the stirrup. 1 By the above describedstructure the line of action is'always vertical and the housing istherefore held vertical at all times;

When used with a 650 pound working load, it'has-been found that sideplates 1, 2 need not be longer than 12",

thus making an extremely compact, lightweight unit which when the ropeis wound unevently on' a drum as in conventional hoists.

extremely importa ntlfeature of the invention is that. the load bearingstirrup and the loaded runiof the wire rope are in perfect verticalalignment as seen in Fig. 4. This constitutes-an extremely beneficialsafety' feature inasmuch as there is no tendency for the hoisting deviceto tilt from an upright position when the load is applied or removed. 77

Although the invention has been described and illustrated in detail,such is' not to be taken as restrictive thereof, since it is obviousthat modifications could be made therein without departing from thespirit and scope of the invention; 1

I'claim: r l.- In' combination with a hoisting device, a housing, aropedrum rotatably supported in said housing and provided with a pluralityof circumferentially extending parallel peripheral grooves, a hoistingrope, said rope being formed intermediate its ends with a'plurality ofaxially spaced loops surrounding said drum with the major portionsofsaid loops received in said grooves, guide slat-7,278

means, carried by said housing engaging thev'junctures connectingadjacentportions of said; loops for leading said rope from one groove tothe adjacent groove, said rope having opposite loaded and unloaded endsextends: ing; outwardly from said, drum whereby said loops are" theonly. connecting means between said rope and sai'clj drum, one of saidgrooves' being formed to a smallet" circumferential extent than. theadjacent groove nearerv said loaded end whereby said rope tightens onsair.lf dru m toward said loaded end assaid" drum rotates. t t

2. In combination with a hoisting device, ahousin'g;

a rope drum-rotatably'supported in said housing 'andprovided' withapluralityof circumferentially extending para allel peripheral grooves,a hoisting rope,, said rope being Wardly'fromsaid drum whereby saidloops are the only connectingmeans between said rope and said drum; saidgrooves. being formed 'to progressively smaller diameters from saidunloaded end toward said loaded end whereby ,said rope progressivelytightens on said drum toward said loaded end as said drum rotates.

3. In combination with a hoisting, device, a housing; a ropedrumrotatably supported in said housing and pro- I vided with a-plurality of circumferentially extendingparallel peripheral grooves, .a' hoistingrope, saidvrope being formed intermediate itsends' with apluralityofaxially spaced loops surrounding said drum with themajor pertions of said loops received-in said' grooves, guide means carried bysaid housing engaging, the junctures' connectin'g'adjacent portions orsaid loops for leading sai d rope fromone groove to the adjacent groove,said rope an ing opposite loaded and 'unloaded ends extending outwardlyfrom said drumwhereby said loops are the:

only connecting means between said rope and said drum,

said grooves being formed to progressively smaller diameters from saidunloaded end toward said loaded end whereby said rope progressivelytightens on'saidf drum toward said loaded end as said drum rotates, thechange in diameter between adjacent grooves being of the order of'afraction of onepercent of the diameterof said drum.

References Cited intthe file of this patent v ,7 UNITED STATES PATENTSMiles Mar. '7, 1922 1,682,083 Johnston "Aug; 28, I928: 2,495,392 SmithJan. 24,1950

2,662,734 Allenbau'gh Dec. 15, 1953

